Navigating spacecraft across the solar system has been
likened to celestial billiards, where an artful "bumper shot" may
be needed to get from one planet to another. A Jet Propulsion
Laboratory spacecraft navigation expert will explain the art and
science of this arcane field in a public lecture called
"Navigation: Cruisin' Through Space," to be held Thursday, Oct.
19 at JPL and Friday, Oct. 20 at Pasadena City College.

Both lectures are at 7 p.m. Parking and admission are free
and on a first-come, first-served basis.

Dr. Donald Gray, veteran of numerous space missions, will
explain how JPL became the world leader in space navigation by
delivering spacecraft to planets, comets, and asteroids
throughout the solar system with unprecedented accuracy. Gray
will also describe experiences that highlight the exuberance,
nail biting, and triumph of innovation inherent in the field.

Gray, who has been with JPL for more than 25 years, has
worked on the navigation teams of the Viking missions to Mars,
the Voyager missions to the outer planets, and the Cassini
mission to Saturn. He is currently working on Genesis, scheduled
to launch next year on a mission to gather a sample of particles
that stream outward from the Sun and return them to Earth for
study.

Gray received a bachelor's degree from the University of
Maryland in 1955, and a master's degree and doctorate in
mechanical engineering from the Massachusetts Institute of
Technology in 1963 and 1967. Gray is the recipient of two NASA
Exceptional Achievement Medals and a NASA Outstanding Leadership
Medal, among the agency's highest honors.

The lecture at JPL will be held in the von Karman
Auditorium, located at 4800 Oak Grove Dr., Pasadena. The
Pasadena City College lecture will be held in The Forum at the
campus, located at 1570 E. Colorado Blvd. in Pasadena. More
information on the von Karman Lecture Series can be found at
http://www.jpl.nasa.gov/lecture or by calling (818) 354-0112.
For directions to JPL, see
http://www.jpl.nasa.gov/tours/routes.html .